Approach to Enhance Raman Shift Accuracy Based on a Real-Time Comparative Measurement Method

A real-time comparative measurement method is proposed to enhance the measurement accuracy of Raman shifts. Several experimental configurations are presented and demonstrated. The error sources in Raman shifts are also analyzed. The method is tested on a Raman spectrometer by measuring a sample of monocrystalline silicon and a sample of polystyrene. Experimental results indicate that the accuracy limit of the method is 0.07 cm–1. The measurement uncertainty of the Raman shift of the silicon is 0.2 cm–1 (k = 2), and the measurement uncertainty of the polystyrene is also improved. It is shown that the real-time comparative measurement method can remarkably enhance the measurement accuracy of Raman shift, and it applies to Raman spectrometers regardless of whether their exact laser wavelengths are known or not.